BULK PROPERTIES OF ALFALFA GRIND IN RELATION TO ITS COMPACTION CHARACTERISTICS

Bulk properties such as bulk and true density, compressibility, asymptotic modulus, and cohesion of alfalfa grinds were determined. These grinds were from low (Ql), medium (Qm), and high (Qh) quality dehydrated alfalfa chops from the 1993-1994 crop year. The Qm grind had the highest bulk and true density (263 kg/m3 and 1300 kg/m3, respectively). The bulk density of Ql and Qh grinds were similar (238 and 236 kg/m3). Ql had the lowest true density (1232 kg/m3) among the grinds. The Jones (1960) and Walker (1923) models were used to characterize the compressibility of the grinds. The Qh grind had the highest compressibility. The Ql grind had the highest asymptotic modulus (EA) values at preset compressive loads of 3000, 4000, and 4400 N. Tensile strength, which measures the degree of compaction of grind particles, showed that the Qh grind had the highest tensile strength, followed by Qm and Ql grinds. Cohesions of Ql grinds which were ground in two hammer mill screen sizes (2.4 and 3.2 mm) were studied. The grind prepared with the 2.4 mm screen size had higher cohesion (2.51 kPa) than the grind from the 3.2 mm screen (2.19 kPa).